Unicode CLDR 21.0 contains data for 193 languages and 170 territories: 528 locales in all. This release did not include a public data submission phase, and focused on improvements to the LDML structure and tools, and consistency of data. Approximately 10,000 data items were removed, and 15,000 added (change in value counts as a removal plus an addition).

Deprecation and removal of whole-locale aliasing, and commonlyUsed elements.

Data for Chinese lunar calendar support.

BCP47 Enhancements

The -t- BCP47 extension for transformed content

Enhanced number system support.

SurveyTool

Major performance enhancements

New <metadata> element in locales for use by Survey Tool (eg, checking capitalization consistency)

Release Numbering

The release numbering changed in this release, from x.y.z to xy.z. Thus the new release number is 21.0 (rather than 2.1.0). This change was made to allow implementations to use 2 numeric subfields for internal numbering, such as 21.0.3.4.

Seed Locales

Locales with insufficient coverage were moved into the "seed" directory, and are not part of the release. The data is available via SVN. There are now 16 such languages and associated regions. When coverage for a seed language improves sufficiently, it will be moved into the release.

Specification

Many clarifications of existing features, such as the use of YY, h, H, K, k in date patterns and skeletons, restrictions on parentLocale, Windows TZID mapping, use of the region code 'UK', the status of non-decimal numbering systems

Deprecation of some structure, such as the 'l' (SMALL LETTER L) pattern character for leap month marker and the commonlyUsed element in formatting short time zone names.